Solutions to this ERROR

[lasto]

Database error

Invalid SQL:
SELECT filename, filesize, postid, attachment.userid,
filedata,
dateline,
visible, mimetype, NOT ISNULL(deletionlog.primaryid) AS isdeleted,doitrepondre
FROM attachment AS attachment
LEFT JOIN attachmenttype AS attachmenttype ON(attachmenttype.extension = SUBSTRING_INDEX(attachment.filename, '.', -1))
LEFT JOIN deletionlog AS deletionlog ON(attachment.postid = deletionlog.primaryid AND type = 'post')
WHERE attachmentid = 4783

mysql error: MySQL client run out of memory

mysql error number: 2008

Board was running fine all week - have added nothing or changed anything then today get the error above when trying to download a rar.
if i try to upload a rar to the board it times out and gives me page not displayed but liek said everything was fine till today.

Any solutions - have emailed host regarding it but waiting on reply so wondering what you lot make of it ??